Normalized Stress–Strain Behavior of Deep-Sea Soft Soils in the Northern South China Sea

Abstract

The study of the physical and mechanical properties of marine soil is of great importance for marine geohazard prediction, submarine energy extraction, and submarine foundation design. In this study, a series of basic geotechnical tests and triaxial compression tests are performed on samples taken from the Shenhu sea area in the South China Sea (SCS). Physical and mechanical properties, particularly normalized stress–strain behavior, are investigated. The microstructural and mineralogical characterization is carried out, through scanning electron microscopy (SEM), and X-ray diffraction (XRD). The results indicated that the sample could be classified as high-plasticity silt (MH) with high water content and high compressibility, that the soil has the highest quartz content in its mineral composition, a loose skeleton composed of flocculent structures under the microscope and is distributed with the remains of marine organisms. Furthermore, a new stress–strain-normalized condition is theoretically derived, based on the hyperbola function. In this condition, the concept of standard normalized factor, which is defined as the ultimate value of principal stress difference, is introduced. Meanwhile, the normalized stress–strain relationship of soft soil from the SCS is established under consolidated undrained conditions and the results of the model are compared with the experimental results, with a good normalization effect. It is believed that the work presented in this paper could contribute to the design and construction of offshore engineering.

Study on the Relationship between Resistivity and the Physical Properties of Seafloor Sediments Based on the Deep Neural Learning Algorithm

“…46. The sediment in the study area has the physical characteristics of a low density, a high water content, and a high compressibility [28].…”

“…The range of the liquidity index was 0.90 to 1.95 and the range of plasticity index was 40.83 to 65.46. The sediment in the study area has the physical characteristics of a low density, a high water content, and a high compressibility [28]. c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, x, y, z are the sediment properties with depth, such as density, water content, porosity, liquid limit, plastic limit, liquid index, plasticity index, shear strength, angle of internal friction, cohesive forces, modulus of compressibility, coefficient of compressibility, effective grain diameter, continuous grain diameter, average particle size, constrained diameter, coefficient of nonuniformity, coefficient of curvature, resistivity, sound attenuation, sound speed).…”

Advances in Marine Engineering: Geological Environment and Hazards

“…Yang et al [12] investigated the physical and mechanical properties of samples taken from the Shenhu sea area in the South China Sea (SCS), particularly normalized stressstrain behavior and microstructural and mineralogical characterization, using a series of basic geotechnical tests, triaxial compression tests, scanning electron microscopy (SEM), and X-ray diffraction (XRD). They discussed the factors and conditions for normalizing the stress-strain relationship in soft soil based on the hyperbolic equation of the stress-strain relationship proposed by Konder, applied the normalization factors to the consolidation undrained test of soft soil in the SCS, and established normalized models to predict the stress-strain relationship.…”

“…The SI includes 1 review paper [1] and 13 research papers [2][3][4][5][6][7][8][9][10][11][12][13][14] that cover different aspects related to the subject. A total of 95 scholars from universities, research institutions, and industries have contributed to this SI.…”

“…The high-quality papers collected in this SI involve many classic and innovative methodologies in this research field, including, but not limited to, analytical and statistical analyses, numerical simulations, laboratory testing, and marine surveys. Specifically, some researchers carried out in situ marine surveys and monitoring [2,3], some implemented discrete element and finite element numerical simulations [4][5][6], some conducted indoor unit tests [7][8][9][10][11][12], some developed laboratory model tests [13,14], and others applied analytical and statistical methods [1,[6][7][8]. These papers represent the state-of-the-art in the latest research concepts, advanced methods, and data that will contribute greatly to the development of the field of marine geological environments and hazards.…”